In the communication industry, the following two modes, one is alternating current input 220 Vac (110 Vac) and the other is direct current input −48 Vdc (−60 Vdc), are usually adopted as power supply for high power equipments. Normally, an integrated equipment requires the width of an embedded power supply subrack (PSS) to be 19 inches or 23 inches so that the PSS can be embedded conveniently into a standard integrated equipment cabinet of 19 or 23 inches wide, and the height of the PSS should be multiple of U (1 U approximately equals to 44.45 mm). The PSS includes at least one power module. Since the input current is usually very high in the high power system, a high power PSS providing alternating or direct current usually adopts multiple parallel power modules and power input cables are directly connected to the power modules, to meet the power supply demand of the integrated equipment.
Two input-output schemes can be adopted for the power modules: front input rear output scheme and rear input rear output scheme. When the front input rear output scheme is adopted, either of the following two connection patterns may be used: according to the first connection pattern, power input cables are connected directly to input terminals of the power modules; according to the second connection pattern, the input terminals at the front end of the power modules are extended to the rear end of the power modules via cables and the power input cables are connected to the input terminals at the rear end. When the rear input rear output scheme is adopted, the power input cables are connected directly to the input terminals at the rear end of the power modules.
For the sake of keeping a neat arrangement at the front end of the equipment, the rear input rear output scheme is usually adopted, or the input terminals at the front end are extended to the rear end of the integrated equipment via cables so as to be connected to the power input cables. FIG. 1 is a schematic illustrating the power input cables connected to the integrated equipment at the rear end in the conventional art. The PSS shown in the figure includes four power modules, each of which is connected to two power input cables. In additional, each of the power modules is connected to a ground wire, or the four power modules share a ground wire. In this way, the PSS is connected to 9 wires at least and even 12 wires. As a result, it can be seen from the back of the PSS that many wires gather at the rear end of the integrated equipment.
Those skilled in the art should know that no universal standard can be set up to define the dimensions of integrated equipments since the integrated equipments vary greatly concerning structure complexity. At present, a universal standard width is adopted by integrated equipments, yet the depths of integrated equipments still vary greatly.
FIG. 2 is the side view of an integrated equipment in the conventional art. It can be seen in the figure that a main machine and a PSS are embedded into the cuboid integrated equipment, the depth of the PSS is essentially identical with that of the integrated equipment and a number of power input cables are connected to the rear end of the PSS. The depth of the integrated equipment is mainly determined by the dimension of the main machine, and the PSS is embedded into the integrated equipment under the main machine. As explained above, the depths of different main machines may vary greatly because of different structure complexity of the main machines and the depths of matched integrated equipments in turn vary greatly. Therefore, the depth of an integrated equipment may be much greater than that of the embedded PSS, and the surface of the rear end of the PSS may be far away from the surface of the rear end of the integrated equipment, as shown in FIG. 3. As a number of power input cables are to be connected to the rear end of the PSS, it will be difficult for operators to connect the power input cables since the power input sockets of the PSS are far away from the surface of the rear end of the integrated equipment and the PSS is usually of low height.
In order to avoid the difficulties of connection operation mentioned above, manufacturers need to produce PSSs of different dimensions for integrated equipments of different dimensions so that each integrated equipment may find the best match as shown in FIG. 2. However, such practice is unsuitable for mass production and the cost of such PSS reproduction is high. It is obvious that the application range of PSS with fixed dimensions in the conventional art is small and usually such PSS is merely suitable to be embedded into an equipment of certain fixed depth.